The present invention relates to a metal laminate gasket containing a thick metal plate with a pre-bent portion around a hole to be sealed.
In metal laminate gaskets formed of a plurality of metal plates, there is a gasket such that one outer plate is turned to have a curved portion and a flange around a hole, and an edge portion of the other outer plate situated above the one outer plate is located under the flange. In this case, a pressure regulation-plate having a hole larger than an outer diameter of the flange is generally disposed between the two outer plates. The pressure regulation plate operates to regulate pressure at the flange. Since the pressure regulation plate does not extend under the flange, it reduces the thickness at the flange as well.
In case the other outer plate is too thick, such as over 0.4 mm, when the gasket is tightened, a large force is required to bend the other outer plate under the flange. In particular, a large surface pressure is concentrated at the edge of the hole of the pressure regulation plate. Thus, when the gasket is installed, a desired surface pressure can not be formed around the hole to be sealed.
In the conventional metal laminate gasket, no specific attention is paid for bending a thick metal plate for the purpose of controlling the surface pressure around a hole to be sealed.
Accordingly, one object of the present invention is to provide a metal laminate gasket, which can provide an adequate surface pressure around a hole to be sealed without local concentration of a surface pressure.
Another object of the invention is to provide a metal laminate gasket as stated above, wherein the surface pressure can be controlled easily as desired.
A further object of the invention is to provide a metal laminate gasket as stated above, which can be easily and economically manufactured.
Further objects and advantages of the invention will be apparent from the following description of the invention.